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docs: adding new guide for namespaces and service discovery (#6788)
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---
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name: '[Enterprise] Register and Discover Services within Namespaces'
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content_length: 8
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id: discovery-namespaces
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products_used:
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- Consul
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description: >-
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In this guide you will register and discover services within a namespace.
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level: Implementation
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---
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!> **Warning:** This guide is a draft and has not been fully tested.
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!> **Warning:** Consul 1.7 is currently a beta release.
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Namespaces allow multiple teams within the same organization to share the same
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Consul datacenter(s) by separating services, key/value pairs, and other Consul
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data per team. This provides operators with the ability to more easily run
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Consul as a service. Namespaces also enable operators to [delegate ACL
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management](/consul/namespaces/secure-namespaces).
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Any service that is not registered in a namespace will be added to the `default`
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namespace. This means that all services are namespaced in Consul 1.7 and newer,
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even if the operator has not created any namespaces.
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By the end of this guide, you will register two services in the Consul catalog:
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one in the `default` namespace and one in an operator-configured namespace.
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After you have registered the services, you will then use the Consul CLI, API
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and UI to discover all the services registered in the Consul catalog.
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## Perquisites
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To complete this guide you will need at least a [local dev
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agent](/consul/getting-started/install) running Consul Enterprise 1.7 or newer.
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Review the documentation for downloading the [Enterprise
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binary](https://www.consul.io/docs/enterprise/index.html#applied-after-bootstrapping).
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You can also use an existing Consul datacenter that is running Consul Enterprise
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1.7 or newer.
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You should have at least one namespace configured. Review the [namespace
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management]() documentation or execute the following command to create a
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namespace.
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```shell
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$ consul namespace create app-team
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```
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## Register services in namespaces
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You can register services in a namespace by using your existing workflow and
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adding namespace information to the registration. There are two ways to add a
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service to a namespace:
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- adding the `namespace` option to the service registration file.
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- using the `namespace` flag with the API or CLI at registration time.
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If you would like to migrate an existing service into a new namespace,
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re-register the service with the new namespace information.
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### Default namespace
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To register a service in the `default` namespace, use your existing registration
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workflow; you do not need to add namespace information. In the example below,
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you will register the `mysql` service in the default namespace.
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First, create a service registration file for the MySQL service and its sidecar
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proxy.
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```hcl
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service {
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name = “mysql"
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port = 9003
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connect {sidecar_proxy}
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}
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```
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Next, register the service and its sidecar proxy using the Consul CLI by
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specifying the registration file.
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```shell
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$ consul services register mysql.hcl
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```
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### App-team namespace
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To register a service in a user-defined namespace, include the namespace in the
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registration file, or pass it with a flag at registration time. In this guide,
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we will include the namespace in the file.
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First, create the service registration file named `wordpress.hcl`. Paste in the
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following registration, which includes the service name and port, and a sidecar
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proxy, along with the namespace.
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```hcl
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service {
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name = “wordpress"
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port = 9003
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connect {sidecar_proxy}
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namespace = "app-team"
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}
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```
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Next register the service and its sidecar proxy.
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```shell
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$ consul services register wordpress.hcl -namespace app-team
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```
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## Discover services
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You can discover namespaced services using all the usual methods for service
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discovery in Consul: the CLI, web UI, DNS interface, and HTTP API.
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### Consul CLI
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To get a list of services in the default namespace use the `consul catalog` CLI
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command. You do not need to add the flag any discover services in the `default`
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namespace.
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```shell
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$ consul catalog services
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consul
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mysql
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mysql-proxy
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```
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Notice that you do not see services that are registered in the app-team
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namespace.
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Add the `-namepsace` flag to discover services within a user-created namespace.
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In the example below, you will use the `-namespace` flag with the CLI to
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discover all services registered in the app-team namespace.
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```shell
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$ consul catalog services -namespace app-team
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consul
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wordpress
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wordpress-proxy
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```
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Notice that you do not see services that are registered in the default
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namespace. To discover all services in the catalog, you will need to query all
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Consul namespaces.
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```shell
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$ consul catalog services
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consul
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mysql
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mysql-proxy
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$ consul catalog services -namespace app-team
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consul
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wordpress
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wordpress-proxy
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```
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### Consul UI
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You can also view namespaced-services in the Consul UI. Select a namespace using
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the drop-down menu at the top of the top navigation. Then go to the “Services”
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tab to see the services within the namespace.
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Before you select a namespace the UI will list the services in the `default`
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namespace.
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### DNS Interface
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~> **Note:** To default to the `namespace` parameter in the DNS query, you must
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set the `prefer_namespace` option to `true` in the [agent's configuration]().
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The new query structure will be, `service.namespace.consul`. This will disable
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the ability to query by datacenter only. However, you can add both namespace and
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datacenter to the query, `service.namespace.datacenter.consul`.
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To discover the location of service instances, you can use the DNS interface.
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```shell
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$ dig 127.0.0.1 -p 8500 wordpress.service.app-team.consul
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<output should show one service>
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```
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If you don’t specify a namespace in the query, you will get results from the
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default namespace.
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```shell
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$ dig 127.0.0.1 -p 8500 wordpress.service.consul
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<output should show no services>
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```
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### Consul HTTP API
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The Consul HTTP API is more verbose than the DNS API; it allows you to discover
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the service locations and additional metadata. To discover service information
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within a namespace, add the `ns=` query parameter to the call.
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```shell
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curl http://127.0.0.1:8500/v1/catalog/service/wordpress?ns=app-team
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<output shows one service>
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```
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## Summary
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In this guide, you registered two services: the WordPress service in the
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app-team namespace and the MySQL service in the `default` namespace. You then
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used the Consul CLI to discover services in both namespaces.
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You can use ACLs to secure access to data, including services, in namespaces.
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After ACLs are enabled, you will be able to restrict access to the namespaces
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and all the data registered in that namespace.
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